In reply to Remi Cornwall's message of Tue, 26 Sep 2006 14:04:36 +0100: Hi, [snip] >Robin, >Yes it is confusing. Also sometimes the phase velocity appears to be greater >than c (anomalous media) or the group velocity is. In either case they defer >to the one less than c. The Feynman articles give a proof relating Quantum >Mechanics (expressions for E and p) to the relation in Special Relativity >that seems to provide a proof that it is the group velocity that is >relevant. > >Remi. [snip] My personal suspicion (and that's all it is), is that the group velocity is responsible for energy transport, and the phase velocity is responsible for information transfer. For a plain wave in empty space the two correspond of course which might explain why the distinction is not so clear.
Regards, Robin van Spaandonk <[EMAIL PROTECTED]>
